NIAMEY, Niger -- France’s Defense Ministry said Monday that French troops had arrived on the outskirts of Mali’s historic Timbuktu, but their rapid advance appeared to have been too late for some of the city’s storied treasures.

As they retreated ahead of French helicopters and paratroopers, militants belonging to al Qaida in the Islamic Maghreb torched the library holding the city’s ancient manuscripts, according to a local journalist who braved the Islamist occupation for nine months but finally decided to flee.

It was a final act of desecration in what many fear will be a string of irreparable destruction meted out by Islamists during the nine months they controlled the city, a desert crossroads that was a center for Islamic scholarship and for centuries connected sub-Saharan Africa to the Mediterranean and the rest of the Eurasia. It captured Europe’s imagination as a far-off mysterious place, earning it U.N. recognition as a world heritage site.

News that the Islamists had destroyed the protected shrines of revered Muslim saints leaked out months ago. But with French troops poised to sweep into the city, the Islamists apparently were furious as they contemplated retreat.

Beginning Thursday, the Islamists unleashed a spree of targeted destruction. They destroyed government offices, laid waste to the local mobile phone networks, vandalized private residences, and destroyed the ferry the city’s residents had used to cross the Niger River.

But the most depressing report for a host of world scholars will be that the Islamists torched the town’s ancient Islamic manuscripts stored at the Ahmed Baba Institute for Documentation and Research, established in 1973 and home to 30,000 scrolls. The manuscripts were brought from “as far as the borders of Mauritania, Burkina Faso, Senegal, Guinea, Niger, Algeria and the Ivory Coast,” said the institute’s website.

The journalist asked to be identified only by his initials, B.M., out of fear of retribution. He managed to escape Timbuktu on Saturday by pretending to be heading toward a nearby village, and then he disappeared and finally caught a bus south. He first gave his account on Monday morning. He was reached again by phone on Monday evening and said he was still making his way to Bamako, Mali’s capital.

The mayor of Timbuktu, Ousmane Halle, who is currently in Bamako, confirmed the journalist’s account over the phone. “That is the same information I have been receiving,” he said.

"The situation is very alarming, that’s why I’m staying here until the situation stabilizes," said the mayor, who has not been able to reach his family by phone after the Islamists destroyed the cellular network’s microwave towers.

The French have advanced on two main fronts, the first east of the Niger River, which cuts through Mali and flows north into the Sahara Desert, and the second to the river’s west. The river whisks past Timbuktu and turns back south toward Gao, northern Mali’s largest town.

The eastern advance first captured Gao. The French now say the western offensive has pushed all the way to Timbuktu, securing the swath of land between the two cities. According to a statement posted on the French Defense Ministry’s website, French forces have secured the airport at Timbuktu and the entrances to the town.

The French already are starting to receive African backup forces that France hopes will soon allow its troops to return home. Troops from neighboring Niger as well as nearby French ally Chad already are holding defensive positions in Mali.